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Feb 05, 2013, 08:54 AM
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sharx's Avatar
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Gee Bee E 59" (Maxford)


Picked up the Gee Bee Model E last Friday at the Maxford warehouse, in Paramount, CA. The complete kit weighs 3 lbs 12oz ( Manufacturer claims 3 lbs 10oz), no electronics, servos and motor though. Just love them GeeBees.

Individual weights:
Cowl ring: 4.5 oz
Landing gear covers (fiberglass): 6.34 oz
Horiz./Vert. Stabilizer: 2.43 oz
supplied Hardware: 8.4 oz
Fuselage: 19.93 oz
Wing: 17.8 oz
Total weight: 3 lbs 12 oz (not including electronics)

First impression:

Likes:
Extremely well packed. The Kit has a beautiful appearance, no wrinkles whatsoever. Fiberglass parts very well made, although on the heavy side. Decals (almost all) already in place. The landing gear has been beefed up from the first prototype and appears to be strong enough.

Dislikes:
Elevator and rudder are actuated by a pushrod, running inside installed plastic tubes. At the rear exit, these tubes exit the fuselage with a tight radius instead of providing a straight guidance for the pushrods, thus creating an unacceptable friction of the control rods. I will replace these tubes with 2 carbon fiber tubes, running straight.
The other thing worth mentioning is the (probably) wrong thrust line. The axis of the motor mounted directly to the firewall points about 1 1/2 degrees to the LEFT instead of having a thrust angle of about 2-3 deg to the RIGHT. In order to correct this misalignment, the motor mount will have to be relocated by about 1/5".

I plan on using the Turnigy Aerodrive SK3 - 3542-800kv Outrunner, providing up to 625 Watts. This motor fits nicely behind the cowl ring.
Maxford states that at least 400 Watts are required (3s). The recommended motor Uranus U35425 is rated at 1100kv. Will be running this plane probably on 4S, using an bigger (and with my motor slower turning) prop to increase the effectiveness.

Looking forward to posts of other builders.
Last edited by sharx; Feb 07, 2013 at 04:53 AM.
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Feb 05, 2013, 03:28 PM
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Too cool.

As much as I dislike ARFs, I love Gee Bees more and was about to pull the trigger on this one. Gonna wait for Charlie to release his ¼ scale Gee Bee E instead.

Looking forward to your progress.



Julian
Feb 06, 2013, 01:41 PM
Übung macht den Meister..
Deuce's Avatar
The exhaust stacks seem a bit excessive! Here's a replica that resides at the Evergreen Air Museum:


I am quite fond of the Gee Bee E model, though! One of these days I'll manage to build one...

James
Feb 06, 2013, 02:58 PM
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sharx's Avatar
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James, you're right and thanks for the input. Adjusting the length of these stacks is easy. I'll do that.

Markus
Feb 06, 2013, 03:34 PM
Warbird crazy!
new2rc's Avatar
This is a very cool model.
Torn between this and waiting for the TBM Mystery Ship

Found this pick which has the long stingers.
I'll be following your progress Markus.
If you have not seen thier vid check it out. They don't show the landing due to what looked like results of a too far aft CG

John
Feb 19, 2013, 03:14 PM
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Dizzy5's Avatar
Any progress? I'm interested in this bird too!

I bought a 2nd hand Pacific Aeromodel 1/4 scale Gee Bee Y I am working on. It needs recovering unless I can get a good match on the yellow and the wheel pants are all busted up.
Feb 25, 2013, 11:56 AM
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Progress report: Almost there…….

my Gee Bee is just about ready for the maiden flight. The building of the Model E was quite straight forward, no big surprises. This one of the better ARF's I've built so far.

Servo installation:
As I mentioned in my first post,the factory installed plastic tubes for the elevator and rudder pushrod had to be replaced with two carbon tubes supported with a balsa crossmember. The selected Savöx SH-0255MG servos should provide enough power for the elevator and the rudder.
Same size but slightly less powerful servos were installed for the ailerons.

Motor installation:
The weight of used Turnigy Aerodrive SK3 - 3542-800 outrunner is 0.3oz less than the outrunner Uranus U35425 Maxford recommends. A preliminary weight and balance check revealed that the airplane WILL be tail heavy. In order to cope with this problem, the motor and thus the cowl ring were moved forward 1/2" using spacers. Also the thrust line was adjusted to the expected necessary offset of about 2 to 2.5 deg to the right using 2 washers. Flight testing will reveal if this offset is correct. The controller sits as close to the firewall as possible.
Maxford suggests using 3s and a prop diameter of 11 or 12", depending on the motor used. Since the fake cylinders and the huge cowl ring create a lot of drag, I went for a bigger 13x6.5" propeller for effectiveness.

Wing- and tail assembly:
No problems experienced whatsoever. The installation of the landing gear is fairly easy, just follow the manual.

Weight and balance:
Maxford recommends a CG located 2 3/4" (70mm) behind the leading edge which equals an MAC of 25%. After viewing the youtube video of Maxford's 2nd prototype (with an apparent aft CG location!) I decided to stay at 25%, at least for the initial flights. 80 grams (2.8oz) of adhesive steel weights had to be placed into the cowl ring. My 4s 3600mAH battery weighs 407 grams (14.35oz). If you're going to use 3s as Maxford recommends, a lot of additional lead will have to be added to the weights in the cowl ring.

With this 4s 3600mAH battery and including all electronics, the finished plane weighs 5 lbs 8.8oz or 2520 grams, which is a bit heavy, I suppose.
But flight testing will tell…….


Final touches:
Basically, the kit is already quite detailed. I've added an instrument panel, did some touch up on the N-numbers and the 54, added a pilot bust "Z.D. Granville", did some dry brushing on the front of the cylinders and added a stick-on image on the back of the cylinders. The flying wires on the bottom of the wing will be added after the initial flights, since there only "cosmetic".
-----
Over all, I'm quite impressed with the kit. If the plane flies as good as it looks, the I would recommend it to everyone. If anyone is interested, here's the link to the manual http://www.maxfordusa.com/manual/gbem.pdf

For the maiden flight, I have to wait for warmer weather - still lots of snow on our runway .................

Markus
Feb 26, 2013, 10:53 AM
Warbird crazy!
new2rc's Avatar
Looking good Markus!

Best luck on the maiden.

John
Feb 27, 2013, 11:59 PM
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Dizzy5's Avatar
Looking really good! Let us know how your maiden goes. I hope it flies as well as it looks too!
Mar 22, 2013, 12:42 PM
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sharx's Avatar
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Finally, my Gee Bee became airborne for the first time. I had to wait until the snow disappears. The first impressions are quite good.
Here's some information on the set up:

Motor: Turnigy SK - 3542-800 (max recommended power 625 Watts)
Battery: 4S-3600 mAH 30C, weighing 395g
Prop: APC 13 x 6.5"

Power: 595 Watts and 40 A with a medium charged battery, with a fully charged one that should be above 600 Watts.

Take off:
The airplane handles quite nice, even with 3-5 mph crosswind as I hade today on my maiden flight.
The behavior is predictable, due to the short coupled fuselage it is a bit sensitive in pitch. Other than that, the take off of was uneventful. The landing gear is a bit "springy", depending on the surface the airplane will jump a bit but will take a less than perfect landing, I guess.

Flight:
Once accustomed with the controls in flight, there are no big surprises. Even with my high power set up - remember Maxford recommends using a 3S set-up and a 11" od 12" prop - the Gee Bee is not the fastest plane. The vertical performance is only satisfactory, no unlimited vertical climbs possible. But if you like flying scale-like, there is enough power with a 4S set up.
The beautiful dummy motor ring with its cylinders creates a lot of drag. Part of the prop thrust just hits the large frontal area without even contributing to forward speed.
Loops are easily accomplished, rolls will take some coordination.

Approach and landing:
Due to this drag mentioned beforehand, reducing speed is no problem. I've used some power during approach. No bad habits were experienced. Once you drop the power, the beautiful bird wants to sit down. The approach speed is rather low for a plane with this weight, I've had no surprising wing drops during my 4 flights.

Do I recommend the plane:
Yes, I do. If you look for a well crafted plane, then this GeeBee Model E might be for you. If you want to fly 3D, you will have to find another plane. But if you intend to fly it scale-like, then the flight silhouette will please you and impress your flying buddies.
I have some doubts, that this aircraft is powered enough using the 3S setup, recommended in the manual. But who knows….

Have fun and drop a note if you have YOUR Gee Bee in the air.

Markus
Mar 27, 2013, 09:41 PM
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I am interested in this plane and in fact hope to be picking one up soon. With your comment on weight that needed to be added, it makes me think that the motor I was thinking about for this plane might be the best. I was thinking of using the Scorpion SII-3026-890 motor which is a bit more powerful than what you were using and a touch heavier. I am glad you gave your prop recommendation as I was going to go with the 3S and 12 inch but now will go to the 4S and 13 inch prop. I am also considering using the new AR635 receiver that has the AS3X gyro system onboard. This should tame down any bad traits I would imagine. Any thoughts ?
Mar 28, 2013, 02:37 AM
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Quote:
Originally Posted by rocket_33
I am interested in this plane and in fact hope to be picking one up soon. With your comment on weight that needed to be added, it makes me think that the motor I was thinking about for this plane might be the best. I was thinking of using the Scorpion SII-3026-890 motor which is a bit more powerful than what you were using and a touch heavier. I am glad you gave your prop recommendation as I was going to go with the 3S and 12 inch but now will go to the 4S and 13 inch prop. I am also considering using the new AR635 receiver that has the AS3X gyro system onboard. This should tame down any bad traits I would imagine. Any thoughts ?
This motor calculator - http://www.ecalc.ch/motorcalc.htm?ecalc&lang=en - will tell you what to expect from your intended set up. With the Scorpion SII-3026-890 you are going to have ample power for this bird, but with it's huge frontal area it ain't gonna be a pylon racer.
The weight of the Scorpion is about 63 grams heavier than my motor, so you will be able to avoid adding dead weight up front.

As for the gyro system you mentioned, it may be worth a try. I have a similar system from HobbyKing installed, switchable to on or off on the radio but the difference in flight is minimal. I consider the GeeBee pretty stable, I did landings with and without the stabilizer system being switched on. I'll keep track on your progress report.

Markus
Apr 13, 2013, 01:33 PM
Warbird crazy!
new2rc's Avatar
Just beautiful Markus!

What a flying site and great pics.
That is one super looking plane.

Congrats!

John
Apr 14, 2013, 12:06 PM
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Dizzy5's Avatar
Congrats on your maiden! Your Gee Bee looks really good in the air!
Apr 14, 2013, 12:27 PM
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I picked mine up last week, have all of the components and hopefully will have it built in the next week or so. Then will just have to wait for the weather and the field to dry out


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